When a user performs an input operation, such as a touch operation or drag operation, using a touch screen of a display device, the display device executes an operation according to the user's input operation. If a user operates an operation element, such as a button or key, a user can confirm that the display device receives a user's input operation because the operation element is displaced as a result of the user's input operation. However, in operation of a touch screen, such a displacement of an operation element does not occur. Accordingly, there exists a technique for notifying a user that a user's input operation performed using a touch screen is received. In JP-A-2001-265481 a technique is described in which when a user performs an input operation to turn over a page while a page representing electronic information is displayed on a touch screen, an image of a subsequent page is displayed in a stepwise manner while an image of a current page reduces in size gradually.
In the technique described in JP-A-2001-265481, displaying the image of “the subsequent page” represents an execution of the foregoing notification. This image is displayed as a result of receipt of a user's input operation to turn over a page and execution of an operation in accordance with the user's input operation. If this technique is applied, for example, to a user's input operation to acquire a newly arrived email, the foregoing notification requires that an image be displayed as a result of execution of an operation in accordance with the user's input operation; namely, an image representing a newly arrived email. However, this image is not displayed until an operation for receiving from an email server data that represents content of a newly arrived email by communication with the mail server is executed. Thus, a user has to wait until the operation is terminated before receiving the foregoing notification. In addition, as long as the operation is terminated, only an image representing a result of execution of the operation, namely, in this example, an image representing content of a newly arrived email, has to be displayed, without the foregoing notification being executed. Accordingly, an object of the present invention is to notify a user that a user's input operation is received before an operation according to the user's input operation is executed.